What is IR Sensor?




Well, the sensor is the most basic and important element in electronics. Today, we will discuss sensors in this podcast. 

 What is sensor:

  A sensor is an electromechanical device. It senses it's surroundings in terms of a physical parameter or mechanical energy and converts into electrical energy. 

 A vivid number of sensors are available in the market. IR sensor is the most emerging sensor to measure the distance.

 IR sensor:

An infrared sensor is an electronic instrument which is used to sense certain characteristics of its surroundings by either emitting and/or detecting infrared radiation. Infrared sensors are also capable of measuring the heat being emitted by an object and detecting motion.


Principle of Working:
An IR sensor consists of two parts, the emitter circuit and the receiver circuit. This is collectively known as a photo-coupler or an optocoupler.

The emitter is an IR LED and the detector is an IR photodiode. The IR photodiode is sensitive to the IR light emitted by an IR LED. The photodiodes resistance and output voltage change in proportion to the IR light received. This is the underlying working principle of the IR sensor.

The type of incidence can be direct incidence or indirect incidence. Indirect incidence, the IR LED is placed in front of a photodiode with no obstacle in between. In indirect incidence, both the diodes are placed side by side with an opaque object in front of the sensor. The light from the IR LED hits the opaque surface and reflects back to the photodiode.

Principle of working of IR sensor

Definition and relationship to the electromagnetic spectrum. Infrared radiation extends from the nominal red edge of the visible spectrum at 700 nanometers (nm) to 1 mm. This range of wavelengths corresponds to a frequency range of approximately 430 THz down to 300 GHz.

Simple connection of IR sensor:



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